Intraosseous Benign Fibrous Histiocytoma of the Mandible

Abstract

<h3>Introduction</h3> Fibrous histiocytomas are a diverse group of tumors that exhibit fibroblastic and histiocytic differentiation and are considered to be a true neoplasm. Intrabony fibrous histiocytomas of the jaws are rare, with most cases being reported in the femur, tibia, pelvis and occasionally the skull bones. <h3>Material and Methods</h3> This report describes a case of 69 year old male patient who presented with pain in the area of tooth #18 (mandibular left second molar) and an endo-perio lesion that perforated through the cortical bone which appeared to be multilocular on radiographs. Clinically, there was a buccal swelling and when the buccal bifurcation was probed, a 10mm depth was revealed with a purulent exudate emanating from the pocket. The bridge was sectioned at the junction of #19 and 20 pontic followed by extraction of tooth #18. Reflection of the mucosa revealed a large bony lesion destroying the buccal plate of bone in the area of teeth #18 and 19. The purulent material was primarily associated with the tooth #18 and not the overall lesion. The majority of the lesion was enucleated and removed. <h3>Results</h3> Histopathological examination revealed fragments of mildly inflamed connective tissue that demonstrated a focus of spindle or mesenchymal cells proliferating in a whorling or storiform pattern. The tissue contained large scattered deposits of mineralized material and fragments of vital bone. Immunohistochemical stains for Desmin, SMA, CD34 and factor XIIIa were negative while diffusely positive for CD68. The positivity for CD68 demonstrated that the lesion was composed of histiocytic cells. <h3>Conclusions</h3> Benign fibrous histiocytomas of the soft tissues are well recognized entities, the rare intra-bony counterpart shares clinical, radiographic and histological features with odontogenic tumors, non-ossifying fibromas, osteoblastomas and fibrous dysplasia, and therefore should be considered in the differential diagnosis of these lesions.